Rose Bosch had a personal reason for wanting to make The Round-Up (La Rafle), the film that became a surprise hit in her native France: the events it depicts almost changed the course of her own life.

The film is the first to confront directly, almost 70 years on, the events of July 16, 1942, when French police, anticipating rather than acting on the orders of the occupying Germans, launched a pre-dawn raid on Paris' Jewish population. They rounded up more than 13,000 and held them in a stadium near the Eiffel Tower called the Winter Velodrome (in French, Velodrome d'Hiver, or Vel d'Hiv) before shipping them off to Auschwitz.

Bosch's husband, Alain Goldman, who is also the film's producer, was the post-war child of a couple who escaped the round-up, Bosch explains.

"If they had not escaped, he would never have been born, my children would never have been born."

The film is based on the stories of several specific people, foremost among them Jo Weisman, now in his 80s, who was just 11 when he was picked up with his parents, Schmuel and Sura. Much of the story is told from the point of view of young Jo, who escaped from an internment camp en route to the gas chamber.

The child's-eye view of history is plainly important to this former journalist.

"It's the first time in the history of the world that a group has set out on a large scale to attack children with the specific intention of exterminating them," she says. "I think it is that that pushed me to make the film and to make it from the point of view of children."

France's wartime capitulation and collaboration with the Nazis, for which then-President Jacques Chirac officially apologised in 1995, has not been ignored by the country's filmmakers. But Bosch's handsomely mounted historical reconstruction is the first to depict the Vel d'Hiv directly and up close. She is philosophical about why it has taken so long.

"I think that sort of trauma you can only talk about after a certain time has passed. Indeed, many of the people we dealt with were convinced that it was still not the time. But we bet it was and we were right, because three million people showed up in the theatres [in France], which was more than for Schindler's List and more than for The Pianist.

Bosch was not prepared for the impact the film had: "It triggered a national discussion to an extent that we did not expect. We had a two-hour live television debate with politicians, historians, witnesses, survivors. That had never happened before."

The film stars Jean Reno, Melanie Laurent and, perhaps surprisingly in such a solemn film, comedian Gad Elmaleh (Priceless, The Valet and the upcoming Tintin film) as Schmuel Weissman.

"He was perfect," says Bosch. "I sat near him on a flight once and we hit some pretty bad turbulence and his son was getting very frightened. I watched him pulling faces and acting the fool to make the kid laugh and not worry, and I thought, 'my God, that is the character'.

"When I asked him to take the part, he said, 'I am only a comedian'.

"And I told him that if you can get people to laugh, you can get them to cry. It's the same thing."